CZECH POLAR REPORTS 2 (1): 1-7, 2012
Macro- and microelements in soil profile of the moss-covered
area in James Ross Island, Antarctica
Ondřej Zvěřina1, Pavel Coufalík1, Tomáš Vaculovič1, Jan Kuta2, Josef
Zeman3, Josef Komárek1
1
Department of Chemistry, Faculty of Science, Masaryk University, Kotlářská 2,
611 37 Brno, Czech Republic
2
Research Centre for Environmental Chemistry and Ecotoxicology (RECETOX), Faculty
of Science, Masaryk University, Kamenice 126/3, 625 00 Brno, Czech Republic
3
Department of Geological Sciences, Faculty of Science, Masaryk University, Kotlářská
2, 611 37 Brno, Czech Republic
Abstract
The study of Antarctic ecosystem provides a valuable insight into the nature
development on the Earth. Biocenosis formation and colonization of land by organisms
are noticeable especially in newly-deglaciated areas. In this research, soil profile
development in the coastal zone of James Ross Island was investigated. The main
objective was the characterisation of soil horizons. The contents of As, Ca, Cd, Co, Cr,
Cu, Fe, K, Mg, Mn, Ni, P, Se and Zn were measured using ICP-MS technique. Soil
parameters like organic carbon content, pH and content of sub-63 μm fraction were also
determined. Based on the results obtained, the mineral-depleted and mineral-enriched
layers in the soil profile were distinguished. With increasing depth, the shallow soil
profile consisted mainly of weathered regolith. Apparently, the basic processes which
are prerequisite for the development of soil ecosystem in the studied area were
confirmed.
Key words: Soil profile, macroelement, microelement, James Ross Island
Introduction
With exception of coastal oases, the
most of Antarctica's surface is considered
as a polar desert. The Antarctic Peninsula
presents a unique place for the exploration
of newly deglaciated territories. In the last
fifty years, ongoing significant warming
(Turner et al. 2005) enables an investigation of dramatic changes in the
ecosystem. Climatic factors (rainfall, number of non-freezing days), erosion, a presence of soil moisture and a distance from
the coast are critical determinants for the
soil development. A formation of inland
———
soil takes a very long time mainly due to
low temperatures which prevent the
growth of soil microorganisms. Just a
small amount of soil biota occurs in the
surface layer of majority of Antarctic soils.
Therefore, the organisms have a little
impact to soil formation with an exception
of erosive effect of some lichen species
(Cambell et Claridge 1987, Øvstedal et
Smith 2001).
During the summer season, the
temperatures are above freezing point in
the James Ross Island. High temperature
Received June 28, 2012, accepted September 29, 2012.
*
Corresponding author: [email protected]
Acknowledgement: Authors are grateful to Czech Polar project for providing of infrastructure
(Johann Gregor Mendel Station).
1
O. ZVĚŘINA et al.
enables an occurrence of soil water in
liquid form which supports the soil
development, biological and chemical
reactions. In this type of coastal oasis, the
colonization of plants such as algae,
cyanobacteria, mosses and lichens take
place. New soil matter from bedrock is
generated in this locality. Besides, an
organic material is produced by microflora
under propitious conditions. Nevertheless,
the soils are formed in shallow layers only.
The main aim of this research was an
evaluation of composition of upper soil
layer in the maritime area. The subject of
interest was the quantification of macro-
elements and important nutritious microelements (Ca, Co, Fe, K, Mg, Mn, P, Se
and Zn) and other elements without
nutrition contribution (As, Cd, Cr, Cu and
Ni). The second goal is a consideration of
development of weathered profile and soil
horizons.
Background contents of some elements
in Antarctic soils and sediments were
published by several authors (e.g. Bargagli
et al. 1995, 1998 and 1999, Crockett 1998,
Giordano et al. 1999, Negoita et al. 2001,
Ribeiro et al. 2011). Our aim was to
evaluate element content in the soils from
the James Ross Island.
Fig. 1. Location of sampling site on James Ross Island.
Material and Methods
Sampling locality and studied material
The Johann Gregor Mendel Station is
located in the northern part of James Ross
Island in the coastal zone. Sampling site in
the vicinity of Czech polar station in the
altitude of 5 m above sea level was chosen
(Fig. 1). The selected locality is impacted
2
by sea aerosols which affect the chemistry
of soil. Therefore, the studied locality is
enriched by minerals transported by seaspray. Geologically, the island is formed
mainly from basalts and andesites of the
Antarctic Andes (Cambell et Claridge
ELEMENTS IN SOIL HORIZONS
1987). Sampling site is localized in
permanently deglaciated area which is
affected by periodical flooding caused by
melting water from snowfields. The soil
development in maritime zone is significantly influenced by abundant precipitation and higher temperatures in the
comparison with an inland environment.
Those factors make this zone more
favourable for the plant life and enable the
accumulation of organic matter.
The soil profile was taken from the site
covered by a moss (Bryum sp.). A pit was
excavated to the depth of 40 cm and the
samples were collected from a side of the
pit using a stainless steel trowel (Fig. 2).
A special care was taken to avoid any
contamination from material falling down
by the pit sides. The samples were
air-dried at 25°C in the laboratory of J. G.
Mendel station, sieved through 2 mm
nylon sieve (Linker Industrie-Technik,
Germany) and then stored in PE bags at
4°C until the analysis.
Fig. 2. Excavation of sampling pit (Photo: Miloš Barták).
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O. ZVĚŘINA et al.
Analytical methods
The soil samples were digested using
aqua regia according to ISO 11466, which
is the most widely used digestion method.
The weight of 3 g of sample was placed
into 250 ml Erlenmeyer flask and 30 ml of
aqua regia was added. A reflux condenser
was mounted due to reduction of the
evaporation. The flask was left to stay for
16 hours at laboratory temperature. Then,
the mixture was boiled for 2 hours in the
open system. After cooling down, digests
were carefully decanted and diluted to the
volume of 100 ml and analysed
immediately.
Quadrupole
ICP-MS
spectrometer
Agilent 7500 CE (Agilent, Japan) was
used for the determination of selected
elements in soil digestions. The spectrometer is equipped by octopole reaction cell
to avoid isobaric interferences, Babington
nebuliser and double-pass Scott chamber.
The conditions were optimized to obtain
the best signal/noise ratio.
The content of organic carbon was
determined using Vario TOC cube analyser (Elementar, Germany). The weight
of 50 mg of soil was placed onto Ag-foil
and the sample was treated by addition of
0.5 ml HCl and dried for 30 min.
Afterwards, a capsule was formed from
the foil and burned in oxygen flow during
the analysis. The performed measurements
were based on IR absorption of released
CO2.
Results and Discussion
Soil properties
Geologically young soils formed
primarily by physical weathering reflect
the characteristics of its parent material.
The soils in the studied area are based on
basaltic bedrock and soil forming
processes are strongly influenced by climatic conditions. It corresponds to relatively shallow soil profile observed. The
soil horizons were specified by elemental
analysis.
An upper layer of studied profile
contained regolith particles greater than
2 mm. Organic residues of moss thallus
were also present in the surface layer
(0 – 2 cm). The rest of profile showed no
significant differentiation of soil horizons,
and therefore, the horizons were defined
chemically. The color of soil was dark
grey, which could indicate a low oxidation
state of present iron (oxidation processes
are relatively slow in polar conditions). A
low amount of soil particles smaller than
63 μm was found (Table 1). In addition,
the soil also contained stones of parent
4
material and thus, the profile was not
compact and homogeneous. However, the
soil permeability allowed possible secondary mineral enrichment.
Organic carbon content is generally
very low in the Antarctic soils (Campbell
et Claridge 1987). A higher content could
indicate the presence of organisms which
can contribute to the soil-forming processes and biochemical reactions. The
values of total organic carbon (TOC) in
individual layers are listed in Table 1.
TOC in topsoil was 3.3% and was higher
than the range of 0.1 – 1.1% reported by
Bargagli et al. (1998) for soil beneath the
moss cover at Edmonson Point (Victoria
Land). However, in the mentioned work,
upper 3 cm of surface layer was collected
instead of 2 cm in this work. The similar
TOC contents ranging from 0.09 to 2.65%
with the highest TOC levels in upper layer
were reported by Navas et al. (2008) for
sediments samples from Byers and Hurd
peninsulas (Livingston Island).
ELEMENTS IN SOIL HORIZONS
A slightly alkaline pH of antarctic soils
is reported very often (Campbell et
Claridge 1987). Nonetheless, the soil
acidity can vary considerably depending
on the specific local conditions (Claridge
et Campbell 1987). The presence of sea
salts and their solubility are important
factors influencing soil acidity in the
coastal areas. The pH ranged from 6.3 to
8.0 (Table 1) and the alkalinity increased
with the depth. It can be presumed that the
soil has a weak buffering capacity due to
low amount of particles below 63 μm and
low carbon content. Thus, the pH balance
is affected primarily by the presence of
slightly alkaline sea salts. The same trends
of increasing pH value with the depth in
the sediments were reported by Navas et
al. (2008).
subsamples
<63 μm [%]
pH
TOC [%]
0 – 2 cm
1.93
6.5
3.3
2 – 10 cm
2.57
6.3
1.5
10 – 20 cm
4.07
7.7
1.2
20 – 30 cm
3.30
8.0
0.5
30 – 40 cm
0.95
7.9
0.6
Table 1. Soil properties.
Contents of elements
Individual soil horizons were defined
according to the elemental analysis of
collected subsamples (Table 2). The surface layer (0 – 2 cm) can be defined as soil
horizon with mineral depletion. This layer,
however, has a high concentration of
phosphorus, which could be bound probably in organic matter and in emerging
phosphates.
In the following layers (2 – 10 and 10 –
20 cm), the concentration of elements is
typical for the enriched soil horizon. The
higher content of clay minerals containing
Mg, Ca and K, and elements sensitive to
redox potential as Fe, Mn and As can be
observed in these subsamples. Both clay
minerals and iron oxyhydroxides have a
high sorption capacity and can accumulate
heavy metals. The concentration of mentioned elements decreases with increasing
depth of samples (20 – 30 and 30 –
40 cm). Presumably, this horizon corresponds to eroded subsoil with pieces of
parent material and the concentration of
elements is typical for bedrock.
Measured phosphorus contents in the
profile are comparable with the range of
400 – 3710 mg kg-1 obtained for similar
type of samples by Bargagli et al. (1998).
The contents of Fe are slightly lower in
comparison with the mentioned report;
however, iron originates rather from
bedrock and does not evince any substantial nutrition effect. In the another
paper, Bargagli et al. (1999) published the
contents of selected elements in the
surface soil in Victoria Land (continental
Antarctica). Observed calcium levels were
significantly higher than the levels
measured in this work. The same elevated
level was found for potassium. On the
contrary, Mg, Cu, Mn and Zn contents
were consistent. Absolute concentrations
of toxic elements (As, Cu, Cd, Cr, Ni)
were within the range reported by Ribeiro
et al. (2011) in sediment profiles from the
5
O. ZVĚŘINA et al.
Admirality Bay (King George Island). The
total contents of Zn and Cu were
comparable with the levels reported by
Chaparro et al. (2007) for the nearby
Seymour Island, but the content of Cr was
significantly lower in our study area and
Ni level was also slightly lower. The
constant cadmium content among the all
subsamples was notable. Bargagli et al.
(1998) reported a significant accumulation
of Cd in moss, however, in this work,
elevated cadmium level was not observed
in the upper layer enriched by moss
thallus. This fact could be caused by more
intensive water elution in the coastal area
supported by weak acid environment of
surface layer. The chromium content was
almost two orders of magnitude lower in
the comparison with background concentration reported by Crockett (1998) for the
grey soil from McMurdo station. Similarly, lower levels of As, Cu, Fe, Ni and
Zn were also found. Most likely, these
values are influenced by the composition
of source material, since the same elution
ability from the soil can not be assumed
for these elements.
subsample
Ca
Co
Fe
K
Mg
Mn
P
0 – 2 cm
3.3 x103
8.7
26 x103
1.9 x103
5.8 x103
410
1000
2 – 10 cm
3.6 x103
13
35 x103
2.2 x103
8.2 x103
590
720
10 – 20 cm
3.8 x103
13
37 x103
2.2 x103
8.3 x103
600
850
20 – 30 cm
3.3 x103
12
33 x103
1.9 x103
7.6 x103
600
640
30 – 40 cm
3.2 x103
12
32 x103
2.0 x103
7.5 x103
540
600
subsample
Se
Zn
As
Cd
Cr
Cu
Ni
0 – 2 cm
0.3
43
4.6
0.07
2.7
14
19
2 – 10 cm
0.1
56
5.4
0.07
12
17
23
10 – 20 cm
<0.02
57
4.9
0.07
16
20
26
20 – 30 cm
<0.02
52
4.6
0.07
8.0
17
24
30 – 40 cm
<0.02
49
4.5
0.07
4.9
18
24
Table 2. Contents of elements in soil profile in mg kg-1 (RSD for all measurements was < 8 %).
Conclusion
The Antarctic soils represent a unique
component of the fragile Antarctic ecosystem. Just as in desert areas, a comprehensive development of soil is significantly limited by natural conditions.
In this research, the samples from a soil
6
depth profile were collected at the James
Ross Island and characterised with respect
to the evaluation the soil development.
Absolute content of the elements and their
distribution in relation to the depth was
studied. In essence, the studied profile
ELEMENTS IN SOIL HORIZONS
showed a typical features of soil development. Although the profile is shallow
and the possibility of chemical weathering
is limited, it can be expected that chemical
weathering takes place and affects the
formation of soil profile.
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